92camarorv6

hey guys i have a 1992 camaro rs v6 auto speedo worked for years then one day it just stopped so i have tryed two other gauge clusters a 110 v8 tbi car speedo chip and the speedo now i have a 145mph clucster i used the hole unit and swaped in my tech with chip and i made sure i put my odomiter #s into the new unit both the 110mph and now the 145mph just make a humming or buzzing sound when you go down the read and they slowing will come up some but the speeds are way off any ideal im at my end of it and stressed any help is a welcome